1. Technical Field
The invention relates to a liquid crystal device in which liquid crystals are retained between a pair of substrates, and a projection-type display apparatus using the liquid crystal device as a light valve.
2. Related Art
In a liquid crystal device, a first substrate provided with a pixel area in which pixel electrodes are arranged on one side thereof, and a second substrate provided with a common electrode to which common potential is applied are bound and joined by a seal member, and a liquid crystal layer is retained in an area surrounded with the seal member between the first substrate and the second substrate. The liquid crystal device is used as a light valve of a direct view type display apparatus or a projection-type display apparatus.
Power supply or signal input to such a liquid crystal device is performed through a terminal formed on the first substrate. For this reason, a structure is employed, in which the first substrate is provided with a terminal and an inter-substrate connection electrode electrically connected to the terminal, and the inter-substrate connection electrode and the common electrode of the second substrate are electrically connected to each other by the inter-substrate connection member interposed between the first substrate and the second substrate (see International Publication No. WO97/34191).
The first substrate may be provided with a dummy pixel electrode to which common potential is applied, in addition to the pixel electrode (JP-A-2007-304384).
Also in this case, the terminal and the dummy pixel electrode are electrically connected, and the common potential applied to the terminal of the first substrate is supplied to the dummy pixel electrode.
In the liquid crystal device with such a configuration, to form the terminal, the inter-substrate connection electrode, and the dummy pixel electrode, etching is performed in a state where a resist mask is formed on the surface of a conductive film formed on the first substrate, to pattern the conductive film.
However, in the technique described in International Publication No. WO97/34191 and JPA-2007-304384, when the terminal and the inter-substrate connection electrode are formed by conductive films with different standard electrode potentials, there is a problem in which an electrode formed of a conductive film with low standard electrode potential of the terminal and the inter-substrate connection electrode is not formed with high precision. That is, although the terminal and the inter-substrate connection electrode are electrically connected to each other, when the terminal and the inter-substrate connection electrode are formed by conductive films with different standards of electrode potential, and when the terminal and the inter-substrate connection electrode come in contact with a stripper for striping the resist mask (electrolysis solution), an electrochemical corrosion reaction (local battery corrosion reaction) proceeds between the terminal and the inter-substrate connection electrode in the stripper, and the conductive film with low standard electrode potential is eluted into the stripper. Further, not limited to the stripping of the resist mask, the electrochemical corrosion reaction proceeds even when the terminal and the inter-substrate connection electrode come in contact with the etching liquid at the time of wet etching, and the conductive film with low standard electrode potential is eluted into the etching liquid (electrolysis solution). The problem occurs also when the terminal and the dummy pixel electrode are formed by conductive films with different standard electrode potential.
Such a problem may be avoided by employing a configuration of forming the terminal and the inter-substrate connection electrode by the same conductive film or a configuration of forming the terminal and the dummy pixel electrode by the same conductive film. However, there are many cases where it is difficult to form the terminal, the inter-substrate connection electrode, and the dummy pixel electrode by the same conductive film when they are formed together with other electrodes.